Adjustable joist



Jan. 27, 1953 A. s. LAGAARD ADJUSTABLE JOIST Filed Jan. 5 1950 ALEXANDER S.T. LAGAARD Patented Jan. 27, 1953 ADJUSTABLE J OIST Alexander S. T. Lagaard, Minneapolis, Minn., assignor to Richard F. Tickle, Minneapolis, Minn.

Application January 5, 1950, Serial No. 136,905

9 Claims.

1 The herein disclosed invention relates to adjustable joists particularly of the type having adjacent sections each constructed with an upper and a lower chord and with diagonal truss members therebetween and has for an object to provide. adjusting means between the chords whereby one chord may be adjusted independently of the other to vary the camber of the joist.

Another object of the invention resides in constructing the adjoining ends of the upper chords of two adjacent chord sections with abutments extending transversely of the chords and spaced from one another and in further providing spacers therebetween reacting against said abutments, certain of said spacers having contacting surfaces angularly disposed with respect to the direction of extent of said chords and adapted to vary the spacing of said abutments upon relative movement.

A still further object of the invention resides in utilizing as the abutments flanges extending inwardly from said chords and in forming said flanges with aligning holes through which a bolt extends.

An object of the invention resides in constructing the spacers as washers disposed upon said bolt and having contacting spiraling surfaces adapted upon relative rotation of the washers to vary the spacing of said flanges.

Another object of the invention resides in providing restraining means for restraining rotation of one of said washers and in providing torque applying means on the other washer whereby relative movement of the washers may be procured.

Other objects of the invention reside in the novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/or described.

In the drawings has been illustrated a portion of a joist including the end sections and an intermediate section. These sections are constructed in the form of trusses and have upper and lower chords with diagonal chord members therebetween. The lower chords of adjacent sections are connected together by means of plates bolted thereto. These plates and chords have a number of holes in them whereby the sections may be bolted together to vary the length of the truss relative rotation of the washers to vary the spacing of said flanges and to vary the camber of the truss. One of the flanges is set inwardly of the end of the chord from which it issues to form a shoulder thereon and the juxtaposed washer is formed with a corresponding shoulder adapted to engage said shoulder and restrain rotation thereof. The other washer is formed with a series of ,circumferentially arranged holes in which a pin may be inserted for applying torque to said washer to rotatethe same relative to the restrained washer.

In the drawings:

Fig. 1 is an elevational view of a portion of a joist illustrating an embodiment of the invention.

Fig. 2 is a view of a portion of the structure.

shown in Fig. 1 and illustrating the parts in altered position.

Fig. 3 is a perspective view of parts of the joist separated from one another.

Fig. 4 is a cross sectional view taken on line 44 of Fig. 1 and drawn to a greater scale.

Fig. 5 is a perspective view of a modified form of spacer used with the invention.

The joist illustrated in the drawings has been designated in its entirety by the reference numeral A and consists of three joist sections B, C and D. The section C is an intermediate section while the sections B and D are end sections. It will readily be comprehended that these sections may be made in any length and if desired additional sections, similar to section C, may be employed with the invention.

The joist section C comprises an upper chord l0 and a lower chord ll arranged in parallel relation. These chords are constructed from structural members T-shaped in cross section and I which have flanges I2 and I3 and webs l4 and I5 facing one another and with the flanges I2 and I3 outermost; Between the webs l4 and I5 are arranged diagonal truss members [6 which are constructed from a single rod I! provided with bends I8 and which form the truss members I6. The bends of said rods are welded to the webs l4 and i5, or may be secured thereto in any suitable manner. The diagonal truss members It terminate short of the ends [9 and 20 of the chords l0 and II as best shown in Fig. 1 for a purpose which will subsequently become apparent.

The end joist section B is constructed similar to the joist section C and consists of an upper chord 2| and a lower chord 22. These chords are also constructed of structural members T-shaped in cross section and have flanges 23 and 24 and webs 25 and 26. These chords are arranged with the webs 25 and 26 extending toward one another and are disposed in alignment with the chords l9 and II. Diagonal truss members 21 extend between the chords 2| and 22 and similar to the truss members l6 are constructed from a rod 28 formed with bends 29 which are welded to the webs 25 and 26 of the chords 2| and 22. The lower chord 22 is formed with bends 30 and 3| which form in said lower chord an upwardly inclined member 32 and a horizontal portion 33 which lies adjacent the upper chord 2|. These parts are welded together to form a bearing by means of which one end of the joist may be supported on the supporting structure.

Between the chords I and 23 of the truss sections B and C is provided a connection 33 and between the upper chords of sections C and D is provided a similar connection 34. Between the chords and 24 of the truss sections B and C is provided a connection 35 and between the lower chords of the truss sections C and D is provided a connection 36. The connections 33 and 34 being identical and the connections 35 and 36 being identical, only the connections 33 and 35 will be described in detail.

The connection 35 consists of a plate 31 which over-lies the end l9 of the lower chord II of truss section C and the end 38 of the lower chord 22 of truss section B. This plate fits up against the under side of the flanges I3 and 24 of said chords. On the upper sides of these flanges are arranged bars 39 which are of the same length as the plate 31. The bars 39, the flanges 24 and I3 and the plate 31 all have registering holes 40. Bolts 4| may be inserted through the said holes and nuts 42 screwed on said bolts clamp the parts together. The holes 49 are spaced equal distances apart in both the flanges, the plate and bars so that the truss sections may be extended to different lengths as illustrated in Figs. 1 and 2. By this means joists of differing lengths determined by the spacing of the holes 49 can be readily procured.

The connection 33 utilizes two flanges. 44 and 45 which arewelded to the ends l9 and 46 of the upper chords l9 and 2| of the truss sections C and B. The flange 441s at the extreme end of the chord 2| of joist section B while the flange 45 isv set inwardly from the end of the flange |2 of chord l0 of joist section C. This leaves a pro.- jection 41 on the flange |2 which projects out-.. wardly beyond the flange 45. Formed in the flanges 44 and 45 are holes 48 through which a bolt 49 extends. Mounted on this bolt are two spacers 50 and The spacer 5| has a bore55 in the same and through which the bolt 49 extends. This spacer has two spiraling surfaces 55 and 51 which spiral in the same direction. The said spacer further is formed with a shoulder 58 which is adapted to engage a shoulder 59 formed by the underside of the projection 41 of flange |2. These shoulders restrain rotation of the said spacer. The spacer 5| has a surface 60. opposite the surfaces 56-and 51 which is adapted to engage the face SI of the flange 45. The spacer 50 is generally circular in form and has a bore 52 through which the bolt 49 extends. The said spacer has a rear surface 53 at right angle to the bore 52 and which is adapted to seat against the face 54 of the'flange 44. The spacer 50 has two spiraling surfaces 62 and 63 which are adapted to fit against the surfaces 55and 51 of the spacer 5|. When the spacer 50 is rotated relative to the spacer- 5| these surfaces cause the two-spacers to become spread apart and to increase the distance between the two flanges 44 and 45. For the purpose of assisting in rotating the spacer 50 the same is constructed with holes 64 at the periphery of the same and into which a pin may be inserted and the spacer thereby rotated. When the spacers have been spaced the desired distance the entire structure is locked by tightening a nut 65 screwed on the bolt 49.

In Fig. 2 the invention has been shown as applied to the joist sections with the same separated from one another to give a joist of greater length than the length of the joist shown in Fig. 1. In, this case the two ends I9 and 66 of the chords H and 22'have been pulled apart and the bolts 4| inserted into the outermost of the holes 49 to hold these ends separated as illustrated. To take up the additional space between the flanges 44 and 45 two washers 61 have been utilized which are mounted on the bolt 49 and which abut against one another and against the. face 54. on flange 44 and the surface 53 on spacer 59.

In the use of the invention the bolts 4| are in-. serted in the proper holes 40 which give the truss the. desired length. The spacers 59 and 5| are next applied between the flanges 44, and 45 and mounted on the bolt 49. If additional Washers such as the washer 6'! are needed they are also placed on the bolt as shown in Fig. 2. The washer 5i) isv then rotated until the, flanges 44 and become sufficiently spaced to give. the desired camber to the joist. The parts are then looked in ad-..

justed position by screwing up the nut 65 on the bolts 49.

In Fig. 5 a spacer I59 which is a modification of the spacer 59 has been shown. Inasmuch as this spacer issubstantially the same as the spacer 59, the correponding parts will not be describedin detail but the same reference numerals will be used and preceded by the digit 1. In this form of the invention the spacer |59 is constructed without the holes 54 and instead thereof a head 58 is employed which may be square or hexagonal as desired. wrench is applied tothe spacer 50-instead of the pin adapted to cooperate with the hole 54 of the spacer 5|].

The advantages. of the invention are, manifest. By means of the construction employed small variations in the length of the upper chordof'the joist may be procured. whereby the camber of the joist may be adjusted. If, after the structure-is in place, theloading becomes excessive, the cam.- ber maybe further adjusted to level up the floor carried on the same. The parts are easily and readily constructed and may be-fabricated at a nominal expense.

Changes in the specific'form of the invention, as herein described, may be made within the scope of what is claimed without departing from the spirit of the invention.

Having described the invention, what isclaimed as new and desired to be protected by Letters Patent is:

1. In an adjustable joist, a flrstjoist section and a second joist section disposed end to end, each comprising upper and lower chords and diagonal truss members therebetween connections for adjustably connecting the lower chords of the sections together, spaced abutments formed on the upper chords of the sections, said abutments facing one another, spacers between said abutments and reacting againstsaid abutments, certain of said spacers. having smooth contacting surfaces situated angularly relative to the direc-.

In this form of the invention a.

tion of extent of the upper chords and adapted upon movement of one of said spacers in the direction of extent of said surfaces to vary the spac ing of said abutments while the joist is in erected position andclamping means for holding the spacers in adjusted position.

2. In an adjustable joist, a first joist section and a second joist section disposed end to end, each comprising upper and lower chords and diagonal truss members therebetween, connections for adjustably connecting the lower chords of the sections together, spaced abutments formed on the upper chords of the sections, said abutments facing one another, spacers between said abutments and reacting against said abutments, certain of said spacers having smooth contacting surfaces spiraling with respect to an axis extending' in the same direction as the direction of extent of said chords and adapted upon rotation of one spacer relative to the other about said axis to vary the spacing of said abutments while the joist is in erected position, and clamping means for holding the spacers in adjusted position.

3. In an adjustable joist, a first joist section and a second joist section disposed end to end, each comprising upper and lower chords and diagonal truss members therebetween, connections for adjustably connecting the lower chords of the sections together, spaced abutments formed on the upper chords of the sections, said abutments facing one another, spacers between said abutments and reacting against said abutments, certain of said spacers having contacting surfaces spiraling with respect to an axis extending in the same direction as the direction of extent of said chords and adapted upon rotation of one spacer relative to the other about said axis to vary the spacing of said abutments, one of said spacers being fixed relative to the juxtaposed abutments, torque applying means for rotating the other spacer relative to the fixed spacer to vary the spacing of said abutments and clamping means for holding the spacers in adjusted position.

4. In an adjustable joist, a first joist section and a second joist section disposed end to end, each comprising upper and lower chords and diagonal truss members therebetween, connections for adjustably connecting the lower chords of the sections together, spaced abutments formed on the upper chords of the sections, said abutments facing one another, spacers between said abutments and reacting against said abutments, certain of said spacers having contacting surfaces spiraling with respect to an axis extending in the same direction as the direction of extent of said chords and adapted upon rotation of one spacer relative to the other about said axis to vary the spacing of said abutments, a projection on a part fixed relative to one of said chords, a projection on the juxtaposed spacer engaging said first named projection and restraining rotation thereof, torque applyingmeans for rotating the other spacer relative to the restrained spacer to vary the spacing of said abutments, and clamping means for holding the spacers in adjusted position.

5. In an adjustable joist, a first joist section and a second joist section disposed end to end, each comprising upper and lower chords and diagonal truss members therebetween, connections for adjustably connecting the lower chords of the sections together, spaced abutments formed on the upper chords of the sections, said abutments facing one another, spacers between said abutments and reacting against said abutments, certain of 6 said spacers having contacting surfaces spiraling with respect to an axis extending in the same direction as the direction of extent of said chords and adapted upon rotation of one spacer relative to the other about said axis to vary the spacing of said abutments, a shoulder on one of said chords extending transversely thereof, a shoulder on the juxtaposed spacer engaging said first named shoulder and restraining rotation thereof, torque applying means for rotating the other spacer relative to the restrained spacer to vary the spacing of said abutments, and clamping means for holding the spacers in adjusted position.

6. In an adjustable joist, a first joist section and a second joist section disposed end to end, each comprising upper and lower chords and diagonal truss members therebetween, connections for adjustably connecting the lower chords of the sections together, flanges extending downwardly from said chords and spaced from one another said flanges having aligning holes therein, a bolt extending through said holes, washers on said bolt between said flanges and reacting against said flanges, certain of said washers having contacting surfaces spiraling with respect to the axis of said bolt, and adapted upon rotation of one washer relative to the other to vary the spacing of said abutments, restraining means for restraining rotation of one of said washers and torque applying means for rotating the other washer relative to the restrained washer.

'7, In an adjustable joist, a first joist section and a second joist section disposed end to end, each comprising upper and lower chords and diagonal truss members therebetween, connections for adjustably connecting the lower chords of the sections together, flanges extending downwardly from said chords and spaced from one another said flanges having aligning holes therein, a bolt extending through said holes and washers on said bolt between said flanges and reacting against said flanges, certain of said washers having contacting surfaces spiraling with respect to the axis of said bolt, and adapted upon rotation of one washer relative to the other to vary the spacing of said abutments, one of said flanges being set inwardly from the end of the chord from which it issues to form a transverse shoulder on said chord, a shoulder on the juxtaposed washer engaging the shoulder on said chord and torque applying means for rotating the other washer relative to the restrained washer.

8. A camber adjusting device for adjustable joists comprising a first joist section and a second joist section each disposed end to end, each consisting of aligning upper and lower chords with diagonal truss members therebetween together with connections for connecting the lower chords of the sections together, said adjusting device comprising spaced abutments formed with aligning holes and with facing surfaces and extending downwardly from the juxtaposed ends of the upper chords, a clamping bolt extending through the holes in said abutment, two coacting spacers formed with aligning holes and threaded on said bolt, said spacers having thrust resisting end surfaces engaging said surfaces of said abutments and smooth contacting surfaces spiraling with respect to the axis of said bolt and engaging one another, one of said spacers having a shoulder and means fixed relative to the joist and having a shoulder for engagement with the shoulder of the spacer and torque applying means formed on the other spacer for rotating the spacers relative to oneanother while the joistiis in erectedposi-tion to vary thecamber of thejoist.

9. A camber adjusting device for adjustable joistscomprising a first joist section and a second joist section each disposed end to end, each consisting of aligning upper and lower chords with diagonal truss members therebetween together with connections for connecting; the lower chords ofthe sections; together, said adjusting device comprising spaced abutmentsformed with aligning holesand with facing surfaces and extending downwardly from the juxtaposed ends; of the upper chords, locking meansat the locality of the abutment of one of the joist sections; a clamping bolt extending through said holes, two coacting spacers formed with aligning holes threaded; onsaid bolt, saidspacers having thrust resisting end surfaces engaging said surfaces of said abutments. andsmooth contacting surfaces 8'. spiralin with esnect o the a i fj a d bo a in o e an th r, oneo.f1sai.d snwfirs hav omp m n o in mea s oa h ng. w h e lockingmeans of the joist and torque applying REFERENCES CITED The following references. are. of record in. the file of this patent:

UNITED STATES PATENTS Number Name Date 1,964,208 Leland June 26, 1934 2,405,889 Kennedy. Aug. 13, 1946 

